Hematopathology is a specialized field of pathology that focuses on diseases affecting the blood, bone marrow, and lymphoid tissues. This chapter provides a comprehensive review of key hematologic disorders, including anemias, leukemias, lymphomas, and myelodysplastic syndromes. It explores the pathophysiology, clinical presentation, diagnostic criteria, and classification of these conditions, emphasizing the role of peripheral blood smear analysis, bone marrow examination, immunophenotyping, cytogenetics, and molecular studies in diagnosis. Advances in hematopathology have led to improved understanding and refined classification systems, which guide personalized treatment strategies and prognosis assessment. Morphological variations and overlapping features of these disorders are also discussed, highlighting the importance of integrating multiple diagnostic modalities. This chapter aims to provide a structured approach to recognizing and differentiating hematologic diseases, equipping clinicians and pathologists with essential knowledge for accurate diagnosis and effective patient management.